Production of yarns, fabrics, etc., having a basis of organic derivatives of cellulose



Patented May 23, 1939 UNITED STATES PATENT OFFICE PRODUCTION OF YARNS,FABRICS, ETQ,

HAVING A BASIS OF ORGANIC DERIVA- TIVES OF CELLULOSE Henry Dreyfus,Lbndon, England 3 Claims.

This invention relates to improvements in the production of yarns,fabrics and other materials, and is more particularly concerned withprocesses for the production of cellulose derivative yarns,

5 fabrics and other materials, and with the new yarns, fabrics and othermaterials produced thereby.

I have found that the resistance to heat of cellulose acetate yams,fabrics and other materials may be increased by subjecting yarns andother materials to esteriflcation with acid anhydrides, for example bytreatment with diluted acetic anhydride, in the presence of metallichalide catalysts. By this means the melting point and the safe ironingpoint of yarns and similar materials may be increased so that they maybe ironed without damage at higher temperatures than are customary inironing ordinary cellulose acetate arti-' ficial silk. In addition, thetreatment reduces the moisture regain of the materials and they acquirea greater resistance to water,'and have a substantially greaterresistance to the delustring action of hot or boiling aqueous liquids ormoist steam. In addition, the affinity of the materials for dyestuffs ingeneral, and particularly for the dispersed insoluble dyestuffs nowcommonly applied to cellulose acetate, is materially reduced, so that byassociation of the yarns or other materials so treated with yarns orother materials of cellulose acetate or of other organic derivatives ofcellulose untreated by the process, differential dyeing effects areobtainable, whilst at the same time the dye has an aflinity for thewhole of the fabric or other material in which the two types of yarn areassociated. Thus, for instance, light and dark blue shades can beproduced by the immersion in a dyebath containing an SRA blue dyestuffof a fabric containing ordinary acetone-soluble cellu lose acetate yarntogether with the same yarn which has been subjected to the process ofthe invention.

In a similar manner cellulose acetate artificial silk and othermaterials may be treated with other acid anhydrides to produce a similareffect and, in addition, artificial silks and other materials of otherorganic derivatives of cellulose may be subjected to treatment withacetic anhydride or other acid anhydride. Examples of other lowerorganic acid anhydrides which may be employed are propionic and butyricanhydrides.

In addition to increasing the resistance to heat and the resistance towater, the new process has the effect of changing the solubilitycharacteristics of the yarns or similar materials. Thus, for

66 instance, by treating cellulose acetate yam with acetic anhydride orother acid anhydride according to the present invention, a yarn may beproduced which is insoluble or much less soluble in acetone. Similarchanges in the solubility characteristics occur in the treatment ofother yarns used as starting materials in the treatment of theinvention. It is thus possible, according to theinvention, to produceyarns which it is difficult or even impossible tomanufacture by a simplespinning process.

According to the present invention, therefore, artificial yarns, fabricsand other materials having improved properties are obtained byacetylating or otherwise esterifying such materials having a basis of anorganic derivative of cellulose by means of organic acid anhydrides inthe presence of metal halide catalysts. I

The invention will hereinafter be described particularly with referenceto the esterification of theyarns, but it is to be understood that it isalso applicable to fabrics and other materials.

The acetic anhydride or other acid anhydride is diluted with a diluentwhich is a non-solvent for the yarn under treatment and which may beinert thereto, which is particularly useful where the anhydride has astrong swelling or dissolving action upon the yarn, orewhich .may have aswelling action on the yarn. Good results are obtained with hydrocarbondiluents, for example xylene or other homologues of benzene, tetraanddecahydronaphthalenes, and kerosene or other high boiling petroleumhydrocarbons and also ethers, e. g., normal and isobutyl and amylethers, carbon tetrachloride and other non-solvent chlorinatedhydrocarbons.

The degree of dilution may be adjusted so as to prevent swelling or soas to obtain some swelling of the yarn. In any case, it should be suchas to prevent any solution or incipient solution of the yarn or anyfusing together of the filaments, and, further, it may be adjusted toprevent any substantial'change in the lustre or quality of the material.A given amount of acetic anhydride may, for example, be dissolved in '7or 8 or 10 up to 20 times or more its weight of'xylene or otherhydrocarbon. The higher dilutions are particularly conducive to avoidingchange in the lustre and in quality. The amount of acetic anhydride onthe weight of the yarn may vary very considerably, but it is usuallysufilcient to use an amount of anhydride from half to twice the weightofthe material, for example a proportion of 1-1% times its weight.

- the amount of the change in the properties of The proportion may bevaried ac-, cording to the degree of acetylation required and.

'- chloride.

the material which it is desired to bring about. The same considerationsapply with other acid anhydrides.

The reaction may be carried out under atmospheric pressure,sub-atmospheric pressure, or at pressures in excess of atmospheric, forexample pressures of 20 pounds per square inch or more.

Esterification according to the present invention is, as stated above,carried out in thepresence of metal halide catalysts. which areparticularly valuable for the process of the present invention are thehalides of zinc and tin, for example zinc chloride and stannic chloride.'Other catalysts which may be employed either separately or together arethe dro-halide acid is also present in suitable pro-' portions whichwill depend to some extent upon the particular acid employed. Forexample, when acetylating cellulose acetate materials with aceticanhydride using zinc chloride.as a catalyst, suitable proportions ofhydrochloric acid are of the order of 1-5 or 10 molecular proportions ofacid to'l molecular proportion of ziric If hydrobromic or hydriodic acidis employed, in general somewhat higher proportions are desirable thanwith hydrochloric acid under similar conditions. It appears that thepresence of the hydrohalide acid accelerates the reaction so that agiven degree of esterification can be effected in a shorter time.Preferably the hydrohalide acid is introduced into the esterifyingmedium in the form of the dry gaseous hydrogen halide.

The catalyst may be present in the reaction mixture or may be present onthe yarn before it is brought into contact with the reaction mixture.Where the yarn is previously impregnated with the metal halide catalyst,it is preferable to apply a solution of the desired catalyst and todry-the catalyst in the yarn before bringing the yarn into contact withthe reaction medium.

The amdunt of catalyst employed will depend somewhat on the catalyst.'However, the catalysts, for example, zinc chloride,'.stannic chlorideor mixtures thereof with hydrochloric acid are preferably employed inquite low concentrations and are also preferably dissolved in thereactants.

Zinc chloride may, for example, be employed in a concentration in thereagents used for esterification of under 1%. for example .5%. Thecatalyst should not be employed in a sufficiently high concentration tobring about reaction between the anhydride employed and any diluent .ifsuch reaction is possible. For instance, with certain aromatichydrocarbons acetic anhydride will react in the presence of zincchloride and similar acidic catalysts if present in a sufiiciently -highconcentration.

In general the lower the concentration of the esterifying agent orcatalyst, the longer will the time of treatment be. It may, for exampleex;

The catalysts yarns of other esters of cellulose, for instance celluloseformate, propionate, butyrate and the like, and of ethers of cellulose,for instance methyl, ethyl and benzyl celluloses, and of etheresters ofcellulose, e. g., ethyl cellulose acetate.

For the purpose of brevity, the term yarn processes. For example, theyarn subsequent to its manufacture maybe subjected to a stretchingtreatment designed to increase its tenacity, e. g. with the aid of asolution of dioxane or other suitable solvent, or in the presence ofsteam or hot water, as described in U. S. applications S. Nos. 4,510filed February i, 1935 and 4,511 filed February 1, 1935. The stretchingtreatment may, for example, be such as to extendthe yarn by 200-500% oreven 1000% or more of its original length. Such yarns have an extremelyhigh tenacity which is reflected in the final product, treated accordingto the present invention. Such stretched yarns, or even ordinaryartificial silk materials may, if desired, be subjected ,to a

shrinking treatment to increase their extensibility, for example ashrinking treatment carried out with the aid of latent solvents (see U.S. application S. No. 611,240 filed May 13,1932 now Patent No.2,058,422, dated October 2'7, 1936.

The reaction between the cellulose derivative yarn and the aceticanhydride or other acid anhydride may be carried out in any suitablemanner, for example as a batch process. For example hanks may beimmersed for the appropriate period in the esterification mixture, orthe mixture may be pumped or "sucked through a per-' forated bobbin orother package of the yam..

The following examples are given in order to illustrate the invention,but it is to be understood that they do not limit it in any way. Theparts given are by weight in each case.

1 Example 1 70 parts of acetone-soluble cellulose acetate yarn aretreated for about A; of an hour at 20?-25 C. in a solution containing200 parts of acetic anhydride, 800-900 parts of benzene, 10 parts ofzinc chloride and 4 parts of hydrogen chloride. The yarn is thenremoved, washed first with benzene and then with water and dried.

Example 2 20 parts of yarn are treated for about 2 hours at 20-25 C. ina mixture consisting of 400 parts of benzene, parts of acetic anhydride,2 parts of zinc chloride and 0.2 parts of hydrogen chloride.- The yarnis then removed, washed benzene and water and dried.

Example 3 20 parts of yarn are treated for about 2 hours at 20-25 C. ina mixture consisting of 400 parts of benzene, 40 parts of aceticanhydride,'.4 parts of zinc chloride and 1 part of hydrogen chloride.

The yarn is then removed, washed with benzene and water and dried.

The vyarn obtained according to each of the with preceding examples ischloroform-soluble, has an increased acetyl value, an improvedresistance to ironing and to treatment with hot aqueous media and adecreased aflinity for the ordinary 5 cellulose acetate dyestuffs.

While the invention has been described above more particularly withreference to yarns, it may also be applied to films, foils and similarmaterials of cellulose derivatives. The expression 10 "non-solvent"liquid medium as used in the following claims is to'be understood asmeaning a medium which is a non-solvent for the materials being treatedthroughout the whole of the reaction. 15 What I claim and desire tosecure by Letters Patent is:

1. Process forthe production of improved artificial materials, whichcomprises subjecting yarns, threads, fabrics and similar textile mate-20 rials having a basis or acetone-soluble cellulose acetate toacetylation with a non-solvent liquid medium comprising aceticanhydride, an organic diluent, stannic chloride and hydrochloric aciduntil they have a reduced solubility in acetone.

2. Process for the production of improved artiiicial materials, whichcomprises subjecting yarns, threads, fabrics and similar textilematerials having a basis of acetone-soluble cellulose acetate toacetylation with a non-solvent liquid medium comprising aceticanhydride, an organic diluent, zinc chloride and hydrochloric acid untilthey have a reduced solubility in acetone.

3. Process for the production of improved artificial materials, whichcomprises subjecting yarns, threads, fabrics and similar textile materials having a basis 01 acetone-soluble cellulose acetate toacetylationkwith a non-solvent liquid medium comprising aceticanhydride, an organic diluent, a metallic halide and a hydrohalide aciduntil they have a reduced solubility in acetone.

DREYFUS.

